Printing telegraph apparatus



July 8,1941.

E. S. LARSON PRINTING TELEGRAPH APPARATUS Filed May 19, 1938 2 Shgets-Sheet 1 FIG. 1

EDWARD S. LARSON Zia 1,. w 1a. i tL 1. u

w v. i. x v A w A, J u- 1. I a nvwmm ln (Ittomeg July 8, 1941. E. s. LARSON PRINTING TELEGRAPH APPARATUS Filed May 19, 1938 2 Sheets-Sheet 2 FIG. 4

FIG. 2

FIG. 3

INVENTOR.

EDWARD s. LARSON A ORNEY.

Patented July 8, 1941 PRINTING TELEGRAPH APPARATUS Edward S. Larson, Chicago, 111., assignor to Teletype Corporation, Chicago, Ill.,- a corporation oi Delaware Application May 19, 1938,Serial No. 208,761

8 Claims.

This invention relates to printing telegraph apparatus and particularly to printing telegraph apparatus in which the characters are printed in page form from type elements carried upon the periphery of a rotatable and selectively arrestable wheel;

An object of the invention resides in the provision in a printing telegraph receiving unit embodying a type wheel having radially movable type elements, of instrumentalities for actuating said type elements including a print hammer effective by overtravel produced by kinetic energy of the print hammer and of part of the lever system by which motion is transmitted to the print hammer.

Another object of the invention resides in an improved and simplified method of assembling a roller bearing grip clutch.

The invention features, in a printing telegraph receiving unit embodying a type wheel having independently reciprocable character elements, a cam controlled system of levers for imparting reciprocatory movement to a print hammer which reciprocates the type pallets. A yieldable element is included in the system of levers which permit the print hammer and a portion of the lever system to overtravel after the control by the cam has been completed, the yieldable element allowing the print hammer to actuate the selected type element and immediately retracting the print hammer to unoperated position even though the member immediately controlled by the cam may remain in fully operated position.

The invention also features the use of a spider for simplifying the assembly of a roller bearing clutch mechanism, the fingers of the spider receiving the rollers and enabling the compression of springs for the individual rollers by a single operation whereby the roller assembly may be worked into a ring member as a unit without necessitating manipulation of the rollers individually.- The spider becomes a permanent part of the assembly and serves as a retainer for the rollers.

In a copending application, Serial No. 77,796, filed May 4, 1936, by Albert H. Reiber, there is disclosed a type wheel printer with reference to which the present invention stands as an improvement. According to the disclosure of that application the displaceable type elements carried by the type wheel are individually actuated by a pivoted actuating member which is operated by a pivotally mounted impact member or hammer. Operation of the hammer through a full stroke sumcient cause the printing of a character is eflected-by a cam operated bail.

According'to the present invention, a reciprocable printing member is provided for actuating the type elements individually. A ball carries a follower roller which engages the periphery of a printing cam, the bail being biased into engagement with the cam by a tension spring. Operation of the ,printing member is effected when the printing bail cam follower roller rides down an abrupt drop in the printing cam. The

distance through which the, printing bail is operated by its spring is insuflicient to. bring the printing member into engagement with a type element. A spring is interposed betweenthe printing bail and a bell crank to which the printing member is articulated. The combined inertia of the printingmember and of the bell crank to which it. is articulated causes those elements to overtravel, the interposed spring yielding-and permitting the overtravel. The amount of overtravel is sufficient to cause a selected type element to efl'ect printing and the spring which yields and permits, the overtravel immediately retracts the printing element to unoperated position, thereby clearing the path of unoperated type elements so that the type wheel may be rotated to a new position. v

The copending application above-identified discloses a main operating cam assembly which is driven by a continuously rotatable shaft through a spring loaded jaw clutch capable of driving in one direction only. In a copending application, Serial No. 193,642,1lled March 3, 1938, by Albert -H. .Reiber, there is disclosed a similar main operating cam assembly similarly driven. by a jaw clutch.

The cam assembly has secured thereto the inner element of a roller bearing grip clutch the outerelement of which is a ring gear which is secured to the driving gear for the main operating shaft. Roller bearingmembers are urged lay-compression springsinto gripping engagement with theinner and outer members ner roller bearing clutch member and is freely rotatable upon the cam assembly but is not movable axially thereof. After the compression springs have been placed in sockets in the inner clutch member and the rollers have been placed upon the fingers of the spider, the spider may be rotated relative to the inner clutch member in the direction to compress the springs whereby the rollers are worked in close to the surface of the inner clutch member and are prevented from being thrust outwardly by the compression springs. The compression springs exert a frictional retaining force upon the rollers and prevent them from falling from the fingers. The assembled inner clutch member,- spider and rollers may then be inserted into the outer member of the roller bearing clutch and the spider serves as permanent retainer for the rollers.

Certain features of invention disclosed but not claimed herein are also disclosed and are claimed in copending application, Serial No. 193,642 filed March 3, 1938, by Albert H. Reiber, Serial No. 203,021 filed April 20, 1938, by Berthel F. Madsen, Serial No. 204,038 filed April 25, 1938, by Carl A. Levin, Serial No. 210,816 filed May 31, 1938, by Carl W. Swan, and Serial No. 211,496 filed June 3, 1938, by Herman Lotterman.

For a complete understanding of the invention reference may be had to the following detailed description to be interpreted in the light of the accompanying drawings, wherein--- Fig. 1 is a perspective view of the combined transmitting and receiving mechanism 'according to the present invention, certain portions being broken away to clarify the showing;

Fig. 2 is a perspective view to illustrate the method of assembling the roller bearing grip clutch, showing the subassembly of inner clutch member. retaining spider, and rollers about who inserted into the outer clutch member;

Fig. 3 is a perspective view partly in section showing the completely assembled roller bearing grip clutch; and

Fig. 4 is a detail view of. the roller bearing clutch mechanism.

Referring now to the drawings and particularly to Fig. 1, the reference numerals I6 and I1 designate generally the typing unit and keyboard transmitter unit respectively, of a printing telegraph apparatus embodying the present invention. The keyboardtransmitter unit 11 is gener.. ally similar to. the transmitterdisclosed in copending application Serial No. 77,796, filed May 4, 1936 by Albert H. Reiber, and typing unit l6 embodies improvements on the typing unit disclosed in the copending application.

The foundation of the keyboard transmitter unit is the base casting l8 to the forward vertical wall of which is secured a slotted comb 19. A plurality of key levers 2| are pivoted within the casting 18 for rocking. movement in a vertical plane, and these key levers protrude from the interior of base 18 through a slot in comb I9. The key levers 2 I are provided with keytops 22 and are arranged to impart characteristic settings to permutation code bars contained within base 18 as fully disclosed in Patent No. 1,595,472 granted August 10, 1926, to Howard L. Krum. To the code bars are articulated lock levers 23 pivotally supported intermediate their ends and projecting above the upper surface of base casting is through apertures therein. The lock levers 23 are therefore subject to permutative setting by the code bars under the control of key levers 2 l.

The upwardly projecting portions of the lock levers 23 are disposed between brackets 24 and 26 secured to base 18, and aligned with each of the lock levers 23 is a contact controlling lever 21, the levers 21 being pivotally supported by a pivot rod (not shown) extending between brackets 24 and 26. A transmitting contact spring 28 individual to each of the levers 21 is mounted between insulating strips upon laterally extending portions of brackets 24 and 26, as indicated at 29. The upper end of each contact spring 28 engages a gooseneck portion of lever 21 and the flexing of contact spring 28 into and out of engagement with a shorter associated contact spring is controlledby gooseneck lever 21. The rocking of the gooseneck lever 21 is, in turn, controlled by the lock levers through blocking lugs (not shown), a lever 21 being unblocked when its corresponding lock lever is presented in extreme clockwise position and being blocked when its corresponding lock lever is in extreme counterclockwise position.

Bracket 24 and another bracket designated by the reference numeral 5| rotatably support a signal transmitting distributor shaft 32. Near one end shaft 32 has secured thereto a gear 33 to which rotation is continuously imparted by another gear as will presently appear. Adjacent to gear 33, shaft 32 has secured thereto the driving element 34 of a jaw clutch. A driven clutch element 36, slidable upon shaft 32, is keyed to a cam sleeve 31 and is urged toward clutch driv- 'ing element 34 by a compression spring 38'. A

pivoted clutch throwout lever 39 normally holds driven clutch element-36 out of engagement with driving element 34 against the force exerted by compression spring 38. Clutch throwout lever 39 has n a rm 4| which terminates substantially in one gement with an abutment screw 42 carried by a clutch tripping bell crank 43. A depending arm 44 of bell crank 43 has its outer end disposed in the path of a lug 46 carried by a link 41 which enters the keyboard base 18 and is'there connected to a universal bail (not shown). When link 41 is shifted forwardly of the keyboard transmitter base by operation of the universal bail under the control of one of the key levers 2|, it rocks bell crank 43 clockwise which, in turn, trips clutch throwout lever 39 and permits spring 38 to shift driven clutch element 36 into engagement with driving element 34. As link 41 is moved forward, it is cammed downwardly by cooperation of a cam projection 48 with the head of a screw 49 carried by a forwardly extending portion of bracket 26. The camming of link 41 downwardly permits the free end of arm 44 of bell crank 43 to escape from lug 46 so that bell crank 43 may return immediately to its extreme counterclockwise position and permit clutch throwout lever 39 to return immediately into position for arresting the clutch comprising elements 34 and 36 at the conclusion of one revolution thereof, even though a key lever should be held depressed and link 41 retained in its forward position for a prolonged interval of time. Thus the operation of cam sleeve 31 by the jaw clutch is confined to a single revolution in response to each operation of a key lever. A tension spring 51 maintains engagement between cam projection 88 of link 41 and the head of screw 48. a

The cam sleeve 31 carries a lock bail operating cam 52 and a plurality of impulse timing cams 53. Cam 52 controls the operation of a lock bail 54 pivotally supported by brackets 24 and 28, lowering the ball into blocking relation to the lock levers 23 as the cam sleeve 31 begins to ro-- tate, and lifting it at the end of a cycle. The function of the lock ball 54 is to prevent the shifting of lock levers 23 during a cycle of rotation of the impulse timing cams 53 and thus prevent mutilation of a signal combination established by the depression of a key lever 2|. Each of the earns 53 is aligned with one of the transmitting contact control levers 21 and is engaged by a portion of the aligned lever. Each of the cams 53 has a notch 55 in the periphery thereof which,

when presented to the associated transmitting contact control lever 21, releases that lever for rocking movement in counterclockwise direction, and the lever 21 rocks unless restrained by its associated lock lever 23. The recesses 58 in the several cams 53 are arranged spirally about the cam assembly so that the levers 21 are released for rocking movement successively. When a lever 21 is permitted to rock counterclockwise by its cam 33, its contact spring 21 flexes'into engagement with the associated short contact spring and a current impulse is impressed upon the telegraph line, the duration of which corresponds to the interval in which the lever 21 remains in its counterclockwise position. The cams 53 thus distribute to the telegraph line the signal impulses corresponding to a character represented by a key lever depressed. One of the contact controlling levers 21 has no lock lever associated with it and operates invariably once in each cycle of operation of the transmitting cam for impressing on the line the stop impulse.

The principal foundation element of the typing or receiving unit is a casting which mounts on the keyboard base l8 and has a portion 81 located centrally of the base I8 and a portion 62 extending transversely of the base 13 in proximity to the rear edge thereof. Thumb screws are employed for securing the casting comprising portions 6| and 62 to the base l8, one of those screws being indicated at 83. A secondary casting 84 extends transversely of the keyboard base l8 and is secured to portion 82 of the primary casting by any desired means, such as screws. The primary casting supports-all of the power driven shafts, the operating cam assemblies, the selector mechanism, the printing mechanism, and the ribbon feed mechanism. The secondary casting 84 supports the platen carriage and associated mechanism, the signal bells, and a set of levers by which various functions are performed. 1

The primary selector mechanism which integrates the signal combinations generated in the keyboard transmitter mechanism, hereinbefore described, or in a remote transmitter, is indicated generally by the reference numeral 68 and is generally similar to the primary selector mechanism disclosed in the hereinbefore identified co pending application of Albert H. Reiber, Serial No. 77,796. The principal elements of the selector mechanism 88 are a selector cam assembly 81, a selector magnet 83, and a sword and T-lever assembly 89, the last mentioned assembly as well as the selector magnet being supported by a mounting plate 1| carried by the forwardly extending portion 8| of the primary casting. The selector cam assembly 81 is carried by the upper end of a vertically positioned shaft which is rotatably supported in bearing blocks 12 and 13. The selector cam assembly 81 has flanges 14 secured thereto at opposite ends, and in spaced relation to each flange 14- is a flange 18 secured to the shaft which supports the cam assembly 81. A friction disc 11 occupies the space between each of the flanges 14 and the adjacent flange 18. Considerable friction is generated between the discs 11 and those positioned on either side of them so that selector cam assembly 81 will rotate with its supporting shaft except when restrained under the control of selector magnet 88, as is well known in this type of single magnet selector mechanism.

Just above the point at which it enters lower bearing block 12, the shaft has secured thereto a gear 18. An electric motor (not shown) drives a pinion which meshes with gear 18 so that the shaft to which the gear 18 is secured is continuously rotated. It may be added at this point that a gear 19 carried by a stub shaft meshes with gear 18 and that a spiral gear 8| also secured to the stub shaft meshes with gear 33 carried by the transmitter shaft 32. Thus rotation is imparted to the transmitting distributor shaft 32 from the motor pinion through gears 18, 19, 8|, and 33. a

The sword and T-lever mechanism 68 is actuated under the joint control of selector cam assembly 51 and the selector magnet 88 to interpret or'integrate a series of impulses representing a signal combination preparatory to setting T- levers 82 in accordance with the signal combination. Each of the T-levers 32 engages one arm of a transfer bell crank 83, the other arm of which is articulated to one of the notched code 1 discs of a code disc selector mechanism indicated generally by the reference numeral 84.

The code disc selector mechanism 84 has a circular arrangement of vertically positioned stop pins 86 which project through slots in the topmost plate of the mechanism. Stop pins 86 are biased inwardly radially of the code disc selector mechanism and near their upper ends they rest against the edges of shiftable notched code discs as is fully disclosed in the copending application of Albert H. Reiber, Serial No. 77,796. The notching of the code discs is such that for any permutative setting of the discs under the control of T-levers 82 one only of the stop pins finds presented to it an alignment of notches, whereupon the pin therefor enters the alignment of notches under the influence of its biasing spring, its upper end moving inwardly. A type wheel stop arm 81 clamped to type wheel shaft 88 is of such length that in revolving, it just clears those of the stop pins 88 which are held in their outermost positions by the code discs, but finds blocking its path any pin 88which has entered an alignment of notches in the periphery of the code discs. The type wheel shaft 88 extends downwardly through the code disc selector mechanism 84 coaxially thereof and receives a continuous torque from the driving motor through any convenient means, such as a gear carried by the shaft 88 and connected thereto by friction discs, the gear being continuously in mesh with the motor pinion. With this arrangement, the shaft 88 is always prepared to rotate and is free to do so when any stop pin 88 which had been previously selected is moved out of the path f the stop arm 81 upon the resetting of the code dis csz With this arrangement, shaft 88 may be arrested in any angular position in which stop arm 81 encounters a stop pin 86. l

The setting of the T-levers 82 according to the .operation of the sword lever mechanism 09 is application Serial No. 77,796, and. the latter of which carries a locking blade 91 that cooperates with extensions 98 of T-levers 82. Locking blade 91 ordinarily blocks the extensions 98 of T-levers 82 whether they be presented in extreme clockwise or counterclockwise position. The rocking of transfer bail 9| in clockwise direction to effect the resetting of T-levers 82 is accompanied by withdrawal of locking blade 91 out of the path of movement of T-lever extensions 98. When the transfer has been completed, transfer bail 9I returns to its extreme counterclockwise position and locking blade 91 is restored to locking psition with respect to extensions 98. r

The front portion SI of the primary foundation casting for the typing unit has secured thereto spaced brackets IM and I02. A shaft I03 is rotatably supported in vertical position between brackets IOI' and I02. Shaft I03 has secured thereto nearthe lower end a gear I04 which permanently meshes with a gear I06 supported by gear 18 and secured thereto by any desired means, such as screws. The hub of gear I04 has secured thereto the driving portion I01 of a positive engagement clutch mechanism, the driven portion of which is indicated by the reference numeral I08. The driven element I08 maybe f the type disclosed in copending application rial No. 165,437, filed September 24, 1937, by B. F. Madsen, having in its periphery a groove designated I09 in the present application, which receives the portion III of the clutch throwout lever I I2. The portion III of the clutch throwout lever II2 confines driven clutch element I08 to substantially complete engagement with driving element I01 during a cycle of operation following the tripping of the clutch, and prevents acceleration of the driven element of the clutch from the speed imparted to it by the driving element I01, should any torque generated by negative load resulting from the interaction of a cam follower and its cam be applied to the driven clutch element I08. Driven clutch element I08 is slidably splined or keyed to a cam assembly sleeve 3 and is urged into engagement with driving element I01 by compression spring II4.

Clutch throwout lever II2 is carried by the lower end of a pivoted bail N6, the upper pivot of which is indicated II1. At its upper end, bail H8 is provided with an arm II5, the free end of which is disposed in the path of the lowermost cam projection I20 of selector cam assembly 61. Bail H6 is biased in counterclockwise direction by tension spring I2I. When cam projection I20 on selector cam assembly 01'encounters arm II5 of bail IIB, the bail is rocked in clockwise direction, thus withdrawing clutch throwout lever II2 from restraining engagement with the driven clutch element I08 of the clutch on the front shaft, and permitting driven element I08 to move into engagement with driving element I 01 whereby rotation is imparted to cam sleeve II3.

Cam sleeve II3 supports three cams desig nated III, H9, and I25. Cam H9 is engaged by a follower roll I22 carried by an arm I23 secured to transferbail 9|. The direction of rotation of cam sleeve H3 is counterclockwise and cam H9, in being rotated, imparts clockwise rotation to arm I23 and therefore to transfer bail 9|. Trans-' fer bail 9|, as previously set forth, effects the permutational rearrangement of T-levers 82 and therefore the notched code discs in the code disc selector mechanism 84 in accordance with a signal combination which has been integrated in the sword lever mechanism 69.

As previously set forth, there is a shaft rotatably supported in vertical position by bearing blocks 12 and 13 to which the gear 18 is secured. Below bearing block 13 the shaft has secured thereto the driving element I24 of a positive drive clutch, the driven element of which is indicated I29. Driven element I29 is slidably splined or keyed to a main cam assembly I30 and is urged into engagement with driving element I24 by a compression spring I26. The engagement and disengagement of the elements I24 and I29 of the main cam assembly driving clutch mechanism is controlled by a pivoted clutch throwout lever I21 to which is secured an arm I28 that extends forwardly of the typing unit and ter minates in the pathof the apex of cam II8 carried by cam sleeve II3 on the front shaft. As indicated in Fig. 1, inwhich the clutch mechanisms on the front shaft and on the main cam driving shaft are shown in their rest positions, the rest position-of the apex of cam H8 is a small angular distance in counterclockwise direction from the end of arm I 28 which effects the tripping of the main cam clutch comprising elements I24 and I29. Since, as previously stated, cam cylinder II 3 rotates in counterclockwise direction, it will be apparent that cam II8 operates upon arm I28 to effect the tripping of driven clutch element I29 just before cam II8 reaches the end of a cycle of operation.

The bracket IOI which rotatably supports the upper end of shaft. I03 pivotally supports a bail I3I, the pivot being indicated I32. The bail I3! supports a cam follower arm which has been omitted from the showing of Fig.1 for the reason that it would conceal substantial portions of the main cam assembly I30 carried by the rotatable shaft which is supported in bearing blocks 12 and 13. The cam follower arm carries at its free end a follower roll which engages cam I25 at a point between cam assemblies II3 and I 24. The contour of cam I25 comprises a smooth gradual rise and a sharp drop-off, the drop-01f being indicated by a reference numeral I33. As cam I25 rotates counterclockwise, it shifts its follower roll away from the axis of shaft I03 and thus imparts a counterclockwise rotation to bail I 3|. In the rest position of cam I25, the drop-off I33 is a small angular distance beyond the point of engagement of the cam follower roll with cam I25. The tendency of the cam I 25 therefore is to permit bail I 3| to return sharply to its extreme clockwise position just before cam I25 reaches its rest position. However, as will presently appear, a cam included in' the cam assembly I30 assumes control of bail I3I just before the sharp drop-oil I33 in cam I25 is presented to its follower, and the cam in cam assembly I30 holds bail I3I. tion for a predetermined interval and thereafter in extreme counterclockwise posicontrols the restoration of bail I3I to its extreme clockwise position.

Bail III has integral therewith an arm I34 which extends toward the rear of thetyping unit and terminates in a spring hanger hook I36. Hook I36 supports one end of a tension spring I31, the opposite end of which is connected to an arm 4 I38 of a type wheel supporting frame I39.

Frame I39 is provided with a vertically disposed slut I, through which extends a stud I42 supported by a portion of theframe of the typing unit. At the top,.frame I39 has a horizontally extending portion I43 through which type wheel shaft 88 passes and in which is rotatably held the hub of a type wheel I44. Vertically disposed guide pins I46, only one of which appears in Fig. 1, are supported by a stationary bracket I41 at the top of the typing unit and pass through apertures in the horizontal portion I43 of type wheel supporting frame I39. The pins I46 and the-cooperating elements comprising slot HI and stud I42 permit oscillatory movement of frame I39 vertically, and guide the frame in that movement.

Frame I39 is provided with an abutment screw I48 against which arm I34 of bail I3I rests when the bail I3I is in extreme clockwise position and frame I39 is in the lowermost position. When bail I3 I is rocked in counterclockwise direction by cam I25, bail arm I34 tends to move out of engagement with abutment screw I48 and spring I31 tends to be distended. Spring I31, in turn, lifts frame I39,

and thus type wheel I44, the normal position of which is below the printing line, is elevated so as to bring character elements carried upon the pe riphery of the type wheel into position to effect tends to occupy an extreme clockwise position which are disposed in the same vertical plane.

Lower arm I14 enters a slot in a bracket I16, carried by ribbon feed mechanism foundation plate I12, and by means of slotted bracket I16, print hammer I69 is held in a vertical plane and is guided in reciprocatory motion imparted by arm I I68 of bail I6I. The upper arm I13 of print hamf occurs.

mer I69 is longer than the lower arm I14 and extends across the periphery of type wheel I44 and across the upper end of type wheel shaft 88. At. its free end, arm I13 is provided with a depending portion I11 which, in turn, is provided with an arm I18, the location of which is in alignment with the foremost portion of platen I49, which portion is at the level where printing lower edge with a shallow recess I1Il,'the base of printing in a line upon a page carried in engagement with cylindrical platen I49. When bail I3I is restored to its extreme clockwise position, arm I34 engages abutment screw I48 and restores frame I39 to its lowermost position which, in turn, restores type wheel I44 to its lowermost pos tion, whereby each character becomes visible immediately after being printed.

As previously set forth, main cam sleeve I38 is set in operation by the tripping of clutch throwout lever I21 by cam I I8 included in front cam assembly II3 Just before cam II8 reaches its rest position. The uppermost of the cams carried by cam assembly I39, designated I5I, is engaged on the periphery thereof by a follower roll I52 carried at the end of a lever I53 which is pivoted at I54. Lever I53 has integral therewith an arm I56 which is providednear its outer end with a plurality of spring connection apertures I51. Any one of the apertures I51 is adapted to receive one end of a tension spring I58, the other end of which is supported by a spring post I59. Spring I58 biases lever I53 in counterclockwise direction, thus urging cam follower roll I52 into engagement with the periphery of cam I5I,. The several spring mounting apertures I51 in arm I56 of lever I53 are at different .distances from spring post" I59 so that the tension exerted by spring I58 and therefore the tordue applied to lever I53 may be varied.

A print hammer operating bail I6I is pivotally supported by pivot I54 and coaxiallymounted' pivot I62. At its lower end, bail I6I is provided with an arm I63 which supports adjustable abutment screw I64 and also one end of a tension engages an arm I61 of lever I53 and the rearmost end of tension spr ng I66 is also connected to arm I61 of lever I53. With this arrangement, bail I6I which rests upon and slides upon aretainer bar 7 I15 secured to ribbon mechanism base plate I12.

I10 with bar I 15, and the restorational motion may, if desired, be limited by engagement of the other end of recess I18 with bar I15.

The print hammer I69 may be lifted out of its position above the type wheel I44 to permit adjusting or changing the type wheel, by springing the free end of print bail arm upwardly until the rearmost end of recess I16 clears bar I15, whereupon arm I14 of the print hammer may be drawn clear of slotted bracket I16, and the print hammer may be rotated upwardly'in a vertical plane about its pivot of articulation with ball arm I68.

Type wheel I44 may be generally similar to the type wheel disclosed in the hereinbefore identified application of Albert H. Reiber, Serial No. 77,796, and also in application Serial No. 77,794, filed May 4, 1936, by Howard L, Krum et al. As shown in those copending applications and as clearly indicated in Fig. 1 of the present application, type wheel I44 is provided with a plurality of radially disposed type pallets I19 which are reciprocably mounted in radial slots in type wheel I44, and

are provided at their outer ends with type elements I8I. There may be two superposed rows of type pallets I19, and by means of the lifting of type wheel supporting frame I39 by lever I34, either of the rows of type pallets may be brought into alignment with rearwardly presented portion I18 of print hammer I69. For any angular position of arrestment of type wheel I44 by the'cooperation of type wheel stop arm 81 with a selected stop pin 86, two of the type pallets I19 will be directed toward platen I49 in the same vertical plane as print hammer I69. According to the distance that type wheel I44 has been lifted by lever arm I34, the distance being controllable, as will appear later, one or the other of the type pallets I19 will be disposed directly in the path of portion I18 of print hammer I69.

Cam I5I, in its normal or rest position, holds Print hammer I69 is provided in itsprint bail operating lever I59 in extreme clock- 1 wise position in opposition to the tension of I56. Lever I59 imparts counterclockwise move ment to bail I6I through abutment screw I 64. The angular distance through which lever I59 rocks, as cam follower I62 descends to the lowest or innermost point on the periphery of cam II is just short of sufllcient to drive print hammer I69 positively against the time pallet I19 aligned therewith. However, the inertia of bail I" and print hammer I69 causes spring I66 to yield and abutment screw I64 to move out of engagement with arm I61. Thus print hammer I69 overtravels or moves a greater distance than it would if positively interconnected with lever I59, the overtravel being caused by the inertia of bail IN and print hammer I69, and being permitted by spring I66.

As soon as the energygenerated by the inertia of bail I6I and print hammer I69 has been expended, spring I66 withdraws print hammer I69 in the direction of its retracted position until abutment screw I64 'returns into engagement with arm I61 of lever -I 59. The remainder of the movement of print hammer I69 to its rest position is effected by the restoration of lever I 59 to. its extreme clockwise position by cam I5I. The

overtravel in the movement .of print hammer I 69 is sufficient to reciprocate the aligned type pallet I19 radially of type wheel I to effect printing.

During the period of overtravel and restoration,

the free end of arm I19 of print hammer I69 is presented between the type pallets adjacent to that which is being operated, so that the type I wheel I could not be rotated, even if permitted to do so by arm 61, due to the fact that interference between arm I19 of print hammer I69 and adjacent unoperated type pallets would occur. Spring I66 withdraws print hammer I69 from a position of interference with unoperated type pallets much more rapidly than it could be withdrawn if'positively connected to print hammer bail operating lever I59. Thus, with the arrangement hereinbefore described, the print hammer I69 is projected and retracted in the shortest possible interval of time so that more next selection.

In a preceding paragraph, the lifting ofthe 3 stated that the lowering of type wheel supporting frame I99 is controlled by a cam included in the cam assembly I99 on the main shaft.

' This cam is indicated by the reference numeral I96, and is of the internal species having its cam surface on the inside of a depending peripheral flange. The internal cam surface is engaged by a follower roller carried at the free end of an arm I61, secured to type wheel lifting bail I9I. Spring I91 biases bail l3l in clockwise direction as previously set forth and, in so doing, urges the follower roller carried by arm I81 to seek engagement with the internal cam surface of cam I 96. Cam I96 does not have a restricting channel, so that the follower carried by arm I81 is free to be moved away from engagement with the interior of the depending flange of cam I96 when bail I9I is rocked in counterclockwise direction by cam I25. During the initial stages of the lifting of frame I99 by cam I25, cam I66 may be stationary.

About the time that cam I25 has rocked bail III to its extreme counterclockwise position, and before the, drop-off of the cam is presented to its follower roller, the innermost portion of the cam surface. of cam I86 is presented in engagement with the follower roller carried by cam follower arm I81. During the engagement of the follower roller carried by arm I81 with whatever dwell there may be at the innermost portion of the internal cam surface of cam J86, bail I9I will be held inextreme counterclockwise position and lever arm I34 will be held in a corresponding position. As cam I66 continues to rotate and the receding cam surface is presented to its follower (the recession being radially away from the axis of the cam), bail I3I will be restored by a controlled motion to its extreme-clockwise positime may be allowed for the rotation of type wheel I N to the position corresponding to the type wheel to bring either of its two rows of type a the groove or channel I9I tion, and type wheel supportingframe I39 will .be. restored to its lowermost position to render visible the character just previously printed. It will be apparent that when the type wheel frame I99 is being elevated; the cam follower, by means of which the lowering of the frame will subsequently be controlled, is moved out of engagement with its cam surface, and that when the frame I99 is being held in elevated position, and is being lowered, the cam follower by which its elevation was accomplished will be held out of engagement with the elevating cam.

Of the principal mechanisms of the typing unit I 6, there remains for consideration only the function mechanism. This mechanism is, in general, similar in construction andoperation to the function mechanism disclosed in the copending application of Albert H. Reiber, Serial No. 77,796. The function mechanism may be understood to include those mechanisms by which such operations as shift, unshift, carriagereturn, line feed, signal bell operation, and transmitter disablement are selected and accomplished. Those functions which are materially different from the corresponding functions, as'disclosed in the co pending application of Albert H. Reiber, Serial No. 77,796, and which will be described in detail, are shift and unshift, by means of which selection'of characters in the letters or figures bank of type pallets is accomplished.

The selection of a function is accomplished by means of a testing mechanism which is cam controlled. Since the testing operation can be conveniently performed by a groove or channel cam, a channel I9I is provided in the upper surface of print bail operating cam I5I. A cam follower, which could not be shown in Fig. 1', is fitted into in cam I5I, and the follower arm is part of a bail I92 which is operated to test for the selection of .functions, and to condition in accordance with the selection one or more of a plurality of function bars, indicated generally by the reference numeral I93. The manner in which the presence of a function is spaced arms I99 and I91, which comprise a func-' tion bail pivoted upon pivot rod I99. The lower arm I91 of the function ball has integral therewhich is indicated by the reference numeral 2I9,

. and the upper of which is indicated by the referwith an arm I99 at the free end of which is sup- 1 ported a cam follower roller 2". A function cam 292, carried by the main cam sleeve I99, has its periphery engaged by roller 2", and when earn 292 occupies rest position, and I99 and the function bail comprising arms I99 and I91 are'iiisposed in extreme clockwise position.

At their free ends, the arms I99 and I91 sup- 1 port a spring post 299 to which is hookedone selection, is manifested by rotation of one or more of the function bars I99 through a small angular distance in clockwise direction. Such rotational movement brings the conditioned function bar out of alignment with the unselected function bars and into position to initiate or per- Y form its assigned function. Immediately after the conditioning of one of the function bars I99, cam 292 rocks its follower arm 29I and the function bail comprising arms I99 and I91 in counterclockwise direction. Since the function bars I93 are pivotally mounted upon rod I94, carried by bail arms I96 and I91, they are moved endwise toward the rear of the printer as cam follower roller 29I is moved to its outermost position with respect to cam 292. 'Those of the function bars I93 which have not been conditioned by being rocking in clockwise direction are recipro'cated idly while one conditioned function bar I99 initiates or performs the assigned function as a result of the'reciprocatory movement. The rod I94, carried by function bail arms I99 and I91. also is pivotally engaged by a spacing pawl 299 which is reciprocated to effect spacing of the platen carriage as the function bars I93 are reciprocated rearwardly of the printer. The spacing operation and the performance of the several functions exceptingshift and unshift are sufficiently similar to those disclosed in the copending application Serial No. 77,796, that it is considered unnecessary to describe them in detail here. However, the shift and unshift functions will now be described.

The hereinbefore identified stud I42, which guides the type wheel supporting frame I39 in its upward and downward movements, extends through a horizontally extending slot in a slide member 291. The slide member 291 is also provided with an open ended slot 299 through which extends a screw 299, carried by the frame of the typing unit. The stud I42 and screw 299 support the slide member. 291 and guide it throughout a limited sliding movement forwardly and rearwardly of the typing unit.

The slide member 291 has integral therewith a vertically extending arm 2| I. The arm 2 is provided near its upper end with a step out aperture 2 I2. By virtue of the step cutting, two abutments or stop surfaces are provided, the lower of enc'e numeral 2" and is the upper end of the aperture 2 I 2. The type-wheel supporting and lifting frame I99 hasv adjustably secured thereto a bracket 2", which has an arm '2", extending into the aperture 2I2 of the slide member 291. When the type wheel lifting frame I39 is lifted by bail arm I34, operating through spring I31, arm 2" of bfacket2l9 may encounter either of the stop surfaces 2I9 or 2, depending upon whether the slide inember 291 is presented in its rearmost or foremost position, and thereby the type wheel lifting frame I39 will be arrested in either of two positions of elevation while bail arm I94 continues to be rocked to its extreme counterclockwise position; When the type wheel liftin frame I99 is arrested by the lower stop surface 2 I 3 of slide member 291' the upper row of type pallets carried by type wheel I44 is presented in alignment with the operating extension I18 of print hammer I99, and when the frame I39 is permitted to be lifted until its arm 2I1 encounters the uppermost stop surface 2, the lower row of type pallets will be presented in alignment with the print hammer I99, and with the character ,impression level of the platen I29.

The movement of slide member 291 from one to the other of its two positions is accomplished by two levers pivoted upon stud I42, one of the levers being pivotally supported between slide member 291 and-the frame elements which support stud I42 and which, therefore, is behind slide member 291 and cannot be seen in Fig. 1, and

the other of which ispivotally supported between slide member 291 end type wheel lifting frame I99 and is indicated by the reference numeral 2 I8 9 in Fig. l. A screw 2I9 establishes a pivotal interconnection between the slide member 291 and its operating lever .2I8. Lever 2I8 .is provided with 8. depending finger 22 I. The first and second of the function bars I93, counting from the top, each have extending laterally therefrom a lug, one of which appears in Fig. l and is indicated by the reference numeral 222. The depending finger 22] of lever 2 I 8. occupies a position directly in the path of lug 222 when the function'bar which carries lug 222 has been conditioned for function performance by being rocked in clockwise direction preparatory to being moved endwise by cam 292, operating through arm 29I and hail arms I96 and I91. When lever 2I8 is in its extreme counterclockwise position, which is the condition when slide member 291 occupies the rearmost/ of its possible positions, finger 22I is disposed substantially at the limit of movement of lug 222 so that it will not be affected if the function bar by which lug 222 is carried is conditioned and reciprocated. When however, the

slide member'291 occupies the foremost posi tion, lever 2I8 will be presented in extreme clockwise position and its depending'fin er 22I will be positioned to be engaged by lug 222, early in the. cycle of movement of 'that lug rearwardly of the typing unit. ,Under these conditions, counterclockwise movement of lever 2| 8 by lug 222, as it moves rearwardly of the typing unit, will result in rearward movement of slide member 291 whichis articulated to, lever 2I8 by screw 2I9, whereby slide member 291 will be shifted to its rearmost position with stop surface 2I3 in the path of arm 2I1 carried by type wheel lifting frame I39. It will be understood that the timing of the apparatus is such that type wheel supporting frame I39 is held lowered by bail arm I34 when slide member 2|! is shifted so that there shall be no interference between arm 2!! amtthe step-cut portion of aperture 2I2 during the movement of slide member 2|].

The restoration 'of the slide member 2Il! to its forward position is accomplished by the lever which'corresponds to lever 2I8 and which is pivoted between slide member 20! and the frame member which supports stud I22 so that it does not appear in Fig. l. A screw 223 establishes a pivotal connectionbetween this lever and the slide member 291. This pivotal interconnection is above stud I42 so that when the lever is rocked in counterclockwise direction, the slide member 2|! will be moved forwardly of the typing unit to its foremost position. The lower end of the lever which is pivoted to slide member 29! at' 223 may be similar to the lower end of lever 2I8 so that when it is inextreme clockwise position, it will be disposed in the path of the laterally extending projection of that one of the function bars I93, the function of which is to shift the slide member 2|! to its fcremost position to permit the type wheel lifting .frame 139 and the type wheel I44 to be lifted to their uppermost position whereby printing may be effected from the lower row of type pallets.

It will.be apparent from the foregoing description of the levers which'control the shifting of slide member 2II'I'that both of these levers efiect control by being rocked incounterclockwise direction, 'one being operative to shift the slide member 2|! rearwardly and the other being operative to shift it forwardly. It will also be apparent that as either is rocked in counterclockwise direction by'its assigned function bar I93,

the motion which it imparts to the slide member 2|! will cause the other lever to be rocked in tatably supports a square rod 24! which enters platen I49 through one of the hubs therein and passes through a square portion of a tube which extends from end to end of the platen I49. The square shaft 24!, is of suflicient length that it may extend into or through the square portion of the tube on the interior of platen I49 in any position which carriage 238 may occupy in its travel back and forth upon its supporting rails. Square shaft 24! has secured thereto a crank 242 which may be rotated manually to impart rotation to square shaft 24! and, through its cooperation with the square portion of the tube into which it extends, rotation may be imparted to platen I49.

Carriage 236 also supports a paper guiding plate or basket 243 which is disposed below the platen for guiding a page in the printing position and which, in turn, supports pressure rolls 244 clockwise direction so that they will be presented alternately in position to be respective function bars. a

In addition to operating the function levers I93 and the spacing pawl 296. the function bail also operates a ribbon feed lever 226. This lever is pivoted upon a stud 22! fixed to. a stationary portion-of the typing unit and its lower end engages the arms I96 and I9! of the function bail. At its upper end, lever 226 is articulated to a link operated by their 22| which has a slot in which is disposed one end of a ribbon feed lever 229. The ribbon feed mech-- anism which is operated by lever 229 may be substantially identical with that disclosed in the copending application of Albert H. Reiber, Serial No. 77,796. The ribbon feed mechanism supporting plate "2 supports-pairs of vertically disposed pins 23! which serve as guides for the inked ribbon 232, and there is also a semicircular ribbon guide which is supported by the type wheel lifting frame I39 in spaced relation to the type wheel I44 between the type wheel and theplaten I49. Thus, the ribbon guide 233 is lifted each time the type wheel I44 is lifted, and a portion of the rib' bon 232 is always positioned between the type wheel I 44 and the platen I49 so that inked type impressions may be produced upon a page carried by platen I49.

The platen I49 is rotatably supported by the opposed ends. of a carriage 236. The carriageis supported for movement transverselyof the typing unit by rails, one of which is indicated as 23!, secured to the rear casting member 64. The cast ing 64 also supports near-the top thereof a bracket 233 which has a threaded aperture in coaxial relation to the platen I49; A bushing 239 threadedly engages the aperture in bracket 238 and roand paper guide fingers 246. Carriage 236 may have associated therewith character spacing mechanism and line feeding mechanism in accordance with the disclosure of the copending application of Albert H. Reiber, Serial No. 77,796. A rotatable drum 24! is provided for housing a carriage return spring. A carriage return belt 248 has one end secured to the periphery of drum 241 and the other end secured to carriage 236. Terminal blocks and slip connections are provided for connecting the various electrical circuit elements in the keyboard transmitter mechanism and in the typing unit to external circuits. The reference numeral 25! indicates a terminal block which is mounted on the keyboard base casting I9 behind the typing unit. Terminal block 25! has terminals 252 individually engaged connection block 254. Slip connection block 254 is secured to the rear portion 62 of the primary typing unit casting below the secondary or carriage supporting casting 64. The contacts 252 and tongues 253 may form electrical connections between the electromagnet 69 carried by the typing unit and the transmitting contact springs 2! carried by the keyboard base and between the selector magnet and external circuit. Thus, the secondary casting and all of the elements which it supports may be removed from the typing unit without disturbing the electrical connection between the selector magnet 68 and the transmitting contacts and between the external circuit and both the selector magnet and the contacts. Also the entire typing unit may be removed from the keyboard base by removal of the thumb screws 63 whereby the slip connection tongues 253 will be removed from engagement with contacts 252 without disturbing the electrical connections between the transmitting contacts and external circuit. V

The general operation of the typing or receiving unit hereinbefore described is as follows: Permutation code signals impressed upon a telegraph line to which the receiving unit is connected enter the receiving unit at terminals 252 and slip connection 253 and are impressed upon the selector magnet". Gear 19 and the shaft which it drives, being in operation, selector assembly 6! which is friction driven is released for a cycle of operation by the start impulse of a. signal combination in accordance with the wellknown practice employed in the operation of single magnet selector mechanismscontrolled by start-stop signals. As the selector cam assembly 6! rotates, the sword levers contained in the sword lever mechanism 69 are set in characteristic positions according to the signal combination received. Just before the selector cam assembly 01 completes a' cycle of rotation, its cam projection I20 engagesarm II5 of bail H0 and rocks the bail in clockwise direction whereby clutch throwout lever H2 is withdrawn from restraining engagement with driven clutch element I00, carried by the 'front shaft, whereupon the driven element I00 is'shifted into engagement with driving element I0'I',- and cam sleeve H0 is set in operation for a cycle comprising one revolution.

The first operation performed after cam sleeve H9 is set in operation is the clockwise rocking of transfer bail 9|, by transfer cam II9, operating through cam follower roller I22 and follower arm I23. Transfer bail 9I operates to set the code discs contained in the code disc selector mechanism 04 in correspondence with the setting of the sword levers. The shifting of the code discs to accomplish the selection of a new stop pin 00 is accompanied by the camming of the previously selected stop pin into unselected position whereby the restraint upon type wheel stop arm 01 is removed and shaft 84 and type wheel I44'rotate to seek a new stop position. At this time, the type wheel I44 is held .in its lowermost position by the type wheel lifting bail I3I and hail arm I34.

As soon as the transfer has been accomplished, the selector cam barrel 01 may be released for rotation to effect the setting of the sword levers according to a new signal combination. The timing of the operation of selector cam assembly 01 and of cam sleeve IIO carried by front shaft I03 is such, with respect to the speed of operation of transmitting apparatus, in response to which this receiving mechanism is intended to operate, that the transfer has been effected before the selector cam barrel is released by the start impulse of the next signal combination.

A predetermined interval after the transfer operation has been performed, cam I25 begins to rock type wheel lifting bail I3I in counterclockwise direction and the type wheel I44 is elevated into printing position. The position in which the type wheel will be arrested will be determined by the position occupied by slide member 201. Bail I3I will, however, be rocked to extreme clockwise position regardless of the position in which type wheel I44 is arrested, spring I01 yielding to permit the motion of bail I3I to be completed.

A short angular distance before cam I25 has rocked bail I3I to extreme counterclockwise position, cam IIO, carried by cam sleeve II3, enages clutch throwout lever I20 of the clutch which comprises driving element I24 and driven element I29 on the main shaft or inner cam shaft, whereby the main assembly I30 is set in operation. By the time cam I25 has rocked type wheel lifting bail I3I to extreme counterclockwise position, internal cam I00, included in the main cam assembly I30, has assumed control of its 01 between successive code combinations. Cam sleeve IIO may, therefore, begin-its next cycle of rotation before the cam assembly I00, carried by the main or inner shaft, has completed much of its cycle of operation. While cam I00 is holding type wheel I44 elevated, and before cam sleeve 3 can have rotated sufficiently far in the next cycle to operate the transfer bail, the print cam I5I brings its sharp drop off into alignment with roller I52, carried by the print bail operating lever I53, whereupon spring I50 rotates lever I50 sharply in counterclockwise direction and this movement is imparted to print bail IOI, which drives print hammer I09 into engagement with the selected type pallet and which overtravels sufficiently to produce an impact between the selected type pallet and a message page carried by platen I49. At substantially the same time that print cam I5I permits print bail operating lever I53 to be rocked counterclockwise by its spring I50, cam groove I9I, in the upper surface of cam I5I, operates its associated bail I92, which tests for function selection as disclosed in the copending application of Albert H. Reiber, Serial No. 17,796. The effect of such testing is that a function bar I93, which corresponds to a function that may have been found to be selected is rocked clockwise through a small angular distance in opposition to its biasing spring 204, to bring it into position to initiate or perform its function.

Since tension spring I00 is effective substantially instantaneously after the printing of a character to withdraw print hammer I09 to its retracted position, which operation can be performed much more rapidly by spring I00 than it could be by cam I51, operating through bail operating lever I50, the transfer of the next signal combination can be performed sooner after the print operation than it could be with positive printing and retraction of the print hammer. that the transfer of the next signal combination may be performed, the greater is the interval of time that may be allotted for rotation of the type wheel into a new stop position corresponding to the new selection and, therefore, the slower can be the speed of rotation of the type wheel shaft 00. The maintenance of minimum rotational velocities consistent with eflicient operation is desirable in order to minimize inertia effects.

Internal cam I00 is required to bold type wheel I44 elevated only until the print operation has been performed. As cam I5I continues to rotate and restores print bail operating lever I53 to its extreme clockwise position, cam I permits bail I3I and bail arm I34 to return to extreme clockwise position, the restoration not being abrupt nor violent but rather being controlled and gradual.

As set forth in the description of apparatus, cam 202 operates function bail lever arm I99 to reciprocate the spacing pawl 200 and the function bars I90. Immediately after the printing of a character has been accomplished, the carriage 230 may be spaced to bring a blank portion of the page into position to receive the next character. It instead of a character having been selected for printing a function has been selected, and the selection evidenced by the clockwise rocking of the particular function bar by operation of bail I92 substantially simultaneously with the operation of print bail lever I50, the apparatus is conditioned for the performance of the function.

The sooner after the printing operation The operation of lever I 00 by cam 202 is gradual so that there is no abruptness in the performance of the flmction. As the, function bars I02 are moved rearwardly of the typing imit by operation of function lever I00, the one of the function bars I92, which has previouslybeen rocked into effective position, initiates or performs the flmction such as shift, unshift, line feed, carriage return,

and various other desirable functions as disclosed in the copending application of Albert II. Reiber, Serial No. 77,796. The operation of-functlon bail lever I00 is the last operation performed by the cams on cam sleeve I24 before the cams return. to rest position, at which point, clutch throwout lever I21 separates driven clutch element I26 1 from driving element I24.

From the foregoing it will be observed that during the reception of isolated or widely separated signal combinations, there occurs a train of operations for each signal combination which ceived, trips oil. the cam sleeve I I3 on the front actual printing operation. In some printing telegraph receiving apparatus having a single operating cam assembly, such for example, as that exemplified in the copending application Serial No. 77,796, the printing operation is timed to precede the transfer operation in each cycle of the cam assembly so that the printing operation always lags one cam cycle behind the transfer operation, and at the completion of any message, the signal combination for the last character or function remains in storage in the code disc selector mechanism and necessitates the introduction of an idle cycle of the selector cam assembly for its clearing out. In the printing receiver mechanism according to the present invention, the printing operation and also the operation of the function mechanism follows the transfer operation in the general cycle of operation of the mechanism which may be considered as beginning with the starting of the selector cam assembly 61 into rotation and terminating with the arrestment of the cam assembly I30 carried by the main or inner operating shaft. It will thus be apparent that the printer always clears out 1 shaft, and comes to rest. The cams carried by l sleeve. "2 transfer the signal combination to the code disc selector, elevate the type wheel to printing position under the control of the shift 1 and unshift slide member 201, trip off the main f cam assembly onthe inner shaft, and come to j rest. The cams on the main cam sleeve I36 effeet the operation of print hammer I66, test for the presence of a function selection, control the I lowering of the type wheel to its idle position, 1 eifect character spacing and the performance of any function selected, and come to rest. I When, however, signal combinations are being 3 received at substantially maximum frequency, as is the case when the transmitter from which the 1 signals are being received is operated by a perforated tape, or if it is a keyboard transmitter, being operated by a skillful operator, the stop 1 time between cycles of operation of selector cam assembly 67 will be very brief. The stop time 1 between successive cycles of the front cam cylinder H3 and the main cam cylinder I20 will be icorrespondingly brief, but definite phase relationships between all of the cam assemblies willbe maintained. Thus, all of the cam assemblies may be rotating simultaneously, and no two of 1 them may be at rest at the same time. However, i the operations which they control will proceed in i orderly fashion exactly in accordance with the planned timing of the receiving mechanism. Any signal combination introduced at the selector ;magnet 66, whether relating to the printing of i a character or to the performance of a function, have become effective for the purpose for which it was introduced before the completion of jthe operation initiated by the selector cam assembly 67, and there will be no storage of a i nal combination requiring an additional cycle of operation of the selector cam barrel for its clear- :ing out, as is the case in some printing telegraph mechanisms, in which the transfer and printing operations are not assigned to be performed by Qcams included in separate cam assemblies, but are performed by cams included in a single cam assembly, and in which there is insuflicient time between the transfer operation and the end of the cycle of the single cam assembly for the completion of rotation of the type wheel, or other conditioning of the printing element and the and prints in accordance with the last signal combination received and no signal combination is ever left in storage in the selector mechanism.

In the foregoing general description of the printing telegraph apparatus in accordance with the invention, certain details were not described because the description was restricted to Fig. 1 in which those details could not be clearly shown.

They are, however, shown in Figs. 2 and 3 and will now be described having reference particularly to the detailed showings.

In Figs. 2 and 3 are shown the details of a roller bearing grip clutch mechanism which serves as a velocity limiter or brake for the main cam assembly. Interposed between the main cam sleeve I30 and the shaft by which it is supported, there is a sleeve 26I which is fixed to sleeve I20 and is threaded at its lower end. The inner member 262 of a roller bearing grip clutch is threadedly secured to the lower end of sleeve 26I. Member 262 fits into the central aperture of ring I06 and is retained in close proximity to the hub of gear I0 as shown in Fig. 3. Inner clutch member 262 has a plurality of substantially right angled notches cut in the periphery thereof, the faces defining these notches being of unequal lengths, the shorter of the two faces of each notch, designated by the reference numeral 262, extending substantially radially of the member 262. The angularly disposed facese of the notches and the adjacent arcuate inner surface of ring gear I06 define recesses that are generally triangular, being bounded by two plane surfaces and a curved surface. Each of the short faces 263 of the notches in member 262 is recessed to receive and support one end of a compression spring 264. An axially drilled roller bearing 266 is disposed in each of the generally triangular recesses and the compression spring 264 tends to wedge the roller bearing between the long face of the notch and the arcuate internal surface of the ring gear I06.

The lower end of cam sleeve I30 is undercut to provide a shoulder 26'! against which a retainer ring 268 is placed before member 262 is secured to sleeve 26I. Retainer ring 268 fits loosely on the undercut portion of sleeve I30 and is not clamped in place but is free to rotate. Ring 260 serves a a partial cover for rollers 266 and prevents them from escaping from their respective recesses in the event that the entire printing unit is inverted such as, for example, during packing or shipment. Ring 268 has an even more important function which will now be described.

Since roller bearings 266 cannot be inserted into their recesses after member 262 has been placed in position in ring gear I06, the retainer ring 268 preventing this, it is necessary to fit the member 262 and rollers 266 into position in ring gear I06 at the same time. Springs 264 tend to complicate the bringing of the member 262 and the rollers 266 into final position together, by thrusting the rollers 266 out of the positions in which they must be held in order to be inserted with member 262 into gear I06. The insertion of the rollers 266 and member 262 has been simplified by providing ring 268 with depending fingers 269 so that ring 268 may be employed as an implement for locating rollers 266 well into the notches in member 262 and for holding them in such positions in opposition to their compression springs 264 while the subassembly is being inserted into ring gear I06. The rollers 266 are provided with axial bores of sufficient size that the rollers may fit loosely on depending fingers 269 of ring 268.

When it is desired to fit the subassembly comprising clutch sleeve I30, its supporting sleeve 26I, inner clutch member 262 and retaining ring 268, into final position with inner clutch member 262 seated inside ring gear I06, a roller 266 is placed upon each of the fingers 269 of ring 268. As each of the rollers 266 is placed upon its finger 269, its compression spring 264 moves it away from the surface which contains the spring socket. The roller, in being thus moved, may

impart counterclockwise rotation to ring 266 until finger 269 has moved as near to the long surface of the notch in member 262 as the thickness of the wall of roller 266 will permit. Thereafter, spring 264 will frictionally engage the exterior of roller 266, and will also cause it to be gripped between finger 269 and the long face of the notch in member 262, so that the roller will not drop from finger 266 while the other rollers are being placed on their respective fingers, nor while the subassembly is being fitted into ring gear I06. After all of the rollers 266 have been placed upon the fingers 269 ring 266 may be rotated in clockwise direction to compress springs 264 to a considerable extent, thus bringing rollers 266 as close as possible to the radial faces of the notches in inner clutch member 262, at which pointthe recesses which will be formed when member 262 is lowered into ring gear I06 will be of greatest widthr Rollers 266 do not need to be held nor manipulated individually, as ring 268 imparts to all of them the desired movement toward radial faces 263 of the notches. With rollers 266 held well within the confines of the notches in member 262 by ring 268 the assembly may be lowered into ring gear I06, after which the hold upon ring 268 may be released, thus permitting springs 264 to move rollers 266 into frictional engagement with the long faces of the notches and with the internal surface of ring gear I06, ring 268 rotating freely to permit this movement of rollers 266. The positioning of rollers 266 So that they will enter ring gear I06 readily will be simplified if rollers 266 are caused to seek continuous engagement with the long faces of the notches in member 262. This may be accomplished, as shown in Fig. 4, by disposing the sockets or recesses for springs 264 so that the axes of the springs shall be outside the plane in which the axes of the rollers 266 move as the rollers move in contact with the long faces of the notches. It may also be desirable to proportion retainer ring 268 so that its fingers 269 are always inside the axes of springs 264. The fingers may thus form fulcrums about which springs 264 may rock rollers 266 into engagement with the long faces of the notches, but whether or not the fingers form fulcrums for the rollers, the forces exerted by the springs 264 upon the rollers 266 have components which tend to keep the rollers in engagement with the long faces of the notches in member 262. The rollers 266 are thus forced'inwardly sufficiently so that there will be no interference when the roller subassembly is fitted into the ring gear I06.

Further simplification of the insertion of the subassembly comprising inner clutch member 262, rollers 266, and ring 266 into ring gear I 06 may be afforded by providing clearance recesses 210 in ring gear I06. Recesses 210 are cut partially into the inner surface of ring gear I 06 and partially into the upper face thereof, thus providing inwardly sloping cam surfaces. Should there be any tendency of springs 264 to thrust rollers 266 outwardly during insertion of the subassembly into ring gear I06, the sloping cam surfaces will guide the roller 266 down into the interior of ring gear I06, it being understood that the spacing of clearances 210 corresponds with the spacing of rollers 266 and that the subassembly may be placed in such angular position with respect to ring gear I06 that rollers 266 are aligned with the clearances 210 before an attempt is made to insert the subassembly into the ring gear I06. I

An understanding of the exact nature of the clutch by which cam sleeve I30 is driven is prerequisite to an understanding of the utility of the roller bearing grip clutch consisting of member 262, rollers 266, and ring gear I06, the roller bearing clutch being used in the present invention as a brake. Cam sleeve I30 is driven by driving clutch element I24 (Fig. 1) and driven element I29 as previously described. This clutch mechanism is of the well known one-way driving construction. Each tooth of both elements of the clutch has one surface substantially in a plane passing through the axis of the clutch and the other surface oblique thereto. Should any torque be applied to the driven element I29 of the clutch which exceeds the torque applied by the driving element I'24, the sloping surfaces of the teeth of one clutch element may tend to slide upon the sloping surfaces of the teeth of the other clutch element, thus shifting driven element I29 axially away from driving element I24 and compressing spring I26. If the diiferential between the two torques is appreciable, the driven element may be rotated ahead of the driving element a distance equal to the extent of several teeth of the clutch member. A torque of sufficient magnitude to cause driven clutch element I29 to rotate more rapidly than driving element I24 and thus to gain upon it may be generated by a heavily biased cam follower such as the function cam follower I99 and roller 20I (Fig. 1) or the print cam follower I33 and roller I52 riding down a sharply descending slope of their respective cams and thus becoming a negative load upon the driven clutch element I29.

The roller bearing grip clutch hereinbefore described serves as a brake to prevent acceleration of cam assembly sleeve I30 under the influence of negative load upon any of its cams. Whenever cam sleeve I 30 is stationary and the gears I6 and I06 are rotating, inner roller bearing clutch member 262, which is secured to sleeve 26I and therefore indirectly to cam assembly sleeve I30, is also stationary and the frictional engagement between the inner surface of ring gear I06 and rollers 266 tends to move the rollers into the widest portion, of the recesses in which they are'seated, the rollers thus being moved substantially free of inner clutch member 262 so that there is no tendency of gear I06 to impart rotation to the inner clutch member. When cam assembly sleeve I30 is released for rotation and is rotating at the same speed as gear I 06 there is no relative movement between roller bearing clutch member 262 and ring gear I06 and springs 264 tend to wedge rollers 266 between the long faces of the notches in inner clutch member 262 and the inner surface of gear I06. If cam sleeve I30 should be subjected to a torque whichtends to rotate it faster than gears I8 and I06 the frictional engagement of rollers 266 with member 262 tends to increase the wedging of the rollers between member 262 and gear I06 so that a positive lock between inner roller bearing clutch member 262 and gear I06 is established and cam sleeve I 30 is prevented from accelerating in response to the locally applied torque and is held to the speed of rotation of gear I8.

Although specific embodiments of the features of invention have been disclosed and described herein, it will be understood that the invention is not limited to such specific embodiments but is capable of modification, reorganization, rearrangement, and substitution of parts and elements without departing from the spirit of the invention and within the scope of the appended claims. I

What is claimed is:

1. Ina printing telegraph apparatus, a type wheel having movable type elements, a print hammer for actuating said type elements individually, a bell crank to which said print hammer is articulated, means for positively engaging and imparting motion in print hammer operating direction to said bell crank through a predetermined part of its operative stroke, and yieldable means interconnecting said motion imparting means and said bell crank for enabling said bell crank to overtravel said motion imparting means in print hammer operating direction and complete its operative stroke by inertia.

2. In a printing telegraph apparatus-a type wheel having movable type elements, a print hammer for actuating said type elements individually, meansfor actuating said print hammer, a cyclically operable cam, means controlled by said cam for positively engaging and imparting motion in print hammer operating'direction to said print hammer actuating means through a predetermined part of its operative stroke, and yieldable means interconnecting said cam controlled means and said print hammer actuating means for enabling said print hammer actuating means to overtravel said motion imparting means in print hammer operating direction and complete its operative stroke by inertia.

3. In a printing telegraph apparatus, a type wheel having reciprocable type elements, means for imparting reciprocatory movement to said type elements, pivotally mounted means for actuating said type element operating means, a power driven cam follower means for positively engaging and operating said pivotally mounted means through a predetermined part of its oper- I ative stroke, and yieldable means interconnecting said cam follower means and said pivotally mounted means for enabling the pivotally mounted means to overtravel said cam follower means and complete its operative stroke by inertia.

4. In a printing telegraph apparatus, a type wheel having reciprocable type elements, means for imparting reciprocatory movement to said type elements, pivotally mounted means articulated to said type element reciprocating means for imparting movement thereto, a power driven cam, cam follower means engaging said cam and having abutting engagement with said pivotally mounted means through a predetermined part of the operative stroke of said pivotally mounted means, and extensible means interconnecting-said pivotally mounted means and said cam follower means for enabling said pivotally mounted means to overtravel said cam follower means for imparting movement to said type elements and complete its operative stroke by inertia.

5. In a printing telegraph apparatus, a type wheel having reciprocable type elements, reciprocable means for engaging and imparting reciprocatory movement to said type elements individually, pivotally mounted means articulated to said reciprocable means, cam follower means having abutting engagement with said pivotally mounted means, cam means engaged by said follower means for controlling movement of said follower means through a predetermined distance less than that required to engage said reciprocable means with a type element, andextensible means interconnecting said cam follower means and said pivotally mounted means for permitting movement of said pivotally mounted means and saidreciprocable means after movement of said cam follower means through said predetermined distance.

6. In a printing telegraph apparatus, a type wheel having reciprocable type elements, reciprocable means for engaging and imparting movement to said type elements individually, pivotally mounted means articulated to said reciprocable means, cam follower means having a portion abutting said pivotally mounted means, a spring connected between said cam follower means and a fixed part of said printing telegraph apparatus for actuating said cam follower means, cam means for timing the actuation of said cam follower means by said spring and for limiting said 1 actuation to a distance less than sufilcient to means and said pivotally mounted means for permitting overtravel movement of said pivotally mounted means and said reciprocable means after actuation of said cam follower means to its limit.

7. In a printing telegraph apparatus, a type wheel having radially reciprocable type elements, a reciprocable member for engaging and actuating said type elements individually, pivotally mounted means articulated to said reciprocable member, cam follower means having a portion abutting said pivotally mounted means, a spring connected between said cam follower means and a fixed part of said printing telegraph apparatus for actuating said cam follower means, cyclically operable cam means for timing the actuation of said cam follower means and for limiting said actuation to a distance less than sufllcient to bring said reciprocable member into engagement with a type element and for restoring said cam follower means to unoperated position, and yieldable means interconnecting said cam follower means and said pivotally mounted means for permitting overtravel of said pivotally mounted means and said reciprocable member to effect printing from said type element, said yieldable means being effective to retract said reciprocable member independently of control of said cam follower means by said cam means.

8. In a printing telegraph apparatus, a type wheel, a plurality of radially reciprocable type elements carried by said type wheel and having operating shanks extending interiorly of said type wheel, reciprocable means for engaging the inner ends of the shanks of said type elements individually and imparting movement to said type elements, pivotally mounted means articulated to said reclprocable means for reciprocating said means, cam follower means having a portion abutting said pivotally mounted means, a spring connected between said cam follower means and a fixed part of said printing telegraph apparatus for actuating said cam follower means, cam means for normally holding said cam follower means in position to hold said reclprocable means clear of the shanks of said type elements, for timing the actuation of said cam follower means by said spring, for limiting said actuation to a distance less than sufficient to bring said reciprocable means into engagement with a type element and for controlling the restoration of said follower means, and yieldable means interconnecting said cam follower means and said pivotally mounted means for permitting overtravel movement of said pivotally mounted means and said reclprocable means after actuation of said cam follower means to its limit and for retracting said reclprocable means clear of the shank of said type element independently of restoration of said cam follower means to normal position by said cam means.

EDWARD S. LARSON. 

